PFF - Pennock's Fiero Forum, PDA Edition

The Turbo 3500 F23 swap (Page 51/79)

ericjon262

MAR 23, 12:01 AM

I decided not to work on the manifold until I had the parts in to do both of them, instead, I started work on the wiring and plumbing.

I reinstalled the fuel rail I had on the car originally, I don't have time to mess with the other rail, and I know this one works.

or does it... :-o

the rail fittings were hitting the throttle, this makes it a total no-go...

I pulled the plenum back off and realized I hadn't seated the fuel rail in the manifold

I gave the snugged down the rail and gained just enough clearance, there's also no gasket, so I have a smidgen more left to gain.

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This images is larger than 153600 bytes. Click to view.

I then turned my attention to the regulator and flex fuel sensor, after a while of playing with fittings and lots of trial and error, I came up with this:

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and then I remembered the flex sensor is bidirectional, so I flipped it around and now it tucks under the throttle much deeper, and way further out of the way. I'm going to make a small bracket that catches the two lower bolts of the throttle body to hold the sensor in place. I plan to make the feed and return lines out of stainless tube vice the hose pictured, the tube has a smaller OD for a comparable ID, and can fit tighter. there will be a section of hose to allow for some flexibility.

I also made a subharness for the injectors, I need to find a 7 pin connector I can put on the end to allow for the injectors to be changed to a different type without having to cut the harness.

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Other than that, I started terminating the wires into the connectors for the MS3 pro, and made a decision on mounting for the MS3, the MS3 will be mounted under the center console, where the "glovebox" is. this mounting position will require me to no longer have the box, but I don't think I have ever put anything in it anyways, it's kinda awkwardly shaped and positioned.

Will

MAR 23, 10:22 AM

Injector sub-harnesses are SUPER convenient, especially in an engine with goofy injector packaging like the V6/60.

I believe there are 8 pin metri-packs on the market. The injectors are fed by two fuses, so you should have 2 feeds and 6 returns.

ericjon262

MAR 23, 03:58 PM

quote

Originally posted by Will:

Injector sub-harnesses are SUPER convenient, especially in an engine with goofy injector packaging like the V6/60.

I believe there are 8 pin metri-packs on the market. The injectors are fed by two fuses, so you should have 2 feeds and 6 returns.

I was planning on one fuse for all 6, I can't find a reason to do 3 and 3, the powertrain will have it's own fuseblock.

------------------
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pmbrunelle

MAR 23, 06:26 PM

quote

Originally posted by Will:
I believe there are 8 pin metri-packs on the market. The injectors are fed by two fuses, so you should have 2 feeds and 6 returns.

Yup, that's what I have. 8-position Metri-Pack 150:

quote

Originally posted by ericjon262:
I was planning on one fuse for all 6, I can't find a reason to do 3 and 3, the powertrain will have it's own fuseblock.

3+3 would allow for limp-home capability in case of a burned injector fuse.

Otherwise, even with just one fuse for all 6 injectors, it still makes sense to split the power feeds in two upstream of the connector; you'll halve the contact loading this way.

It's not likely that you'll find a 7-position connector anyway; even-numbers are more common, so you might as well use up that 8th spot for something.

[This message has been edited by pmbrunelle (edited 03-23-2020).]

Will

MAR 23, 08:09 PM

quote

Originally posted by ericjon262:

I was planning on one fuse for all 6, I can't find a reason to do 3 and 3, the powertrain will have it's own fuseblock.

GM used two fuses... I wouldn't second guess them on basic stuff...

If you get up to 80% DC on your injectors, then you'll have 4.8 injectors on at the same time. That's either all 4.8 on your single feed or two feeds each with 2.4 injectors on at once.

[This message has been edited by Will (edited 03-23-2020).]

ericjon262

MAR 23, 08:12 PM

quote

Originally posted by pmbrunelle:

3+3 would allow for limp-home capability in case of a burned injector fuse.

Otherwise, even with just one fuse for all 6 injectors, it still makes sense to split the power feeds in two upstream of the connector; you'll halve the contact loading this way.

It's not likely that you'll find a 7-position connector anyway; even-numbers are more common, so you might as well use up that 8th spot for something.

I highly doubt I'll split the injector power out, I usually keep spare fuses in my cars anyways, and there's not a snowballs chance in hell that I'll drive it with 3 dead cylinders.

As for the connector, I was planning a GT series 8 pin connector like this, with one terminal plugged:

https://www.eficonnection.c...led-female-connector

pmbrunelle

MAR 23, 08:58 PM

See this document for connector part numbers, and temperature derating curves for contact load:
https://www.powerandsignal....Global%20Catalog.pdf

For my Fiero project, I selected Metri-Pack 150/280 as a supplemental series of connectors due to the parts commonality (some cable seals) and tooling commonality (crimping tool) with the Weather Pack connectors that are already on the car. This choice reduced my inventory and tooling expense.

GT is a worthy competitor, but it is distinct from the Weather Pack series, so you'll need separate parts and tools.

[This message has been edited by pmbrunelle (edited 03-23-2020).]

ericjon262

MAR 23, 09:07 PM

quote

Originally posted by pmbrunelle:

See this document for connector part numbers, and temperature derating curves for contact load:
https://www.powerandsignal....Global%20Catalog.pdf

For my Fiero project, I selected Metri-Pack 150/280 as a supplemental series of connectors due to the parts commonality (some cable seals) and tooling commonality (crimping tool) with the Weather Pack connectors that are already on the car. This choice reduced my inventory and tooling expense.

GT is a worthy competitor, but it is distinct from the Weather Pack series, so you'll need separate parts and tools.

at this point, most of my car is GT connectors, and I already have a bunch of terminals, seals and connectors. on top of that, I really like the GT series because they are easily re pinned or disassembled, some of the metri pack stuff you can't repin (pull to seat)

that document is useful, thanks!

pmbrunelle

MAR 24, 06:42 PM

quote

Originally posted by Will:
If you get up to 80% DC on your injectors, then you'll have 4.8 injectors on at the same time. That's either all 4.8 on your single feed or two feeds each with 2.4 injectors on at once.

Electrical contacts touching each other only do so at the asperities. The areas where there is electrical contact are called a-spots.

Since all the electrical current flows through the asperities (having a small cross-sectional area), the asperities become the hot spots due to resistive heating.

The softening/melting temperature of the asperities determines the maximum allowable current of a pair of contacts. Obviously, ambient temperature plays into the allowable current.

Physically speaking, the asperities are very small... they have low mass. It does not take long to bring up the temperature of the asperities; we say that the asperities have a fast thermal time constant.

Since the thermal time constant of the asperities is fast, I don't think it's appropriate to consider a time-averaged value like you have done. If 6 injectors can be on at any given time, you should design for a load of 6.0 injectors, not 4.8.

I followed a class on contacts, and I asked the guru who was teaching, well what about an alternating current in the low MHz range? Even there, alternating current is not equivalent to direct current having the same RMS value, because of the asperities' temperature variations within the cycle.

With an 80% duty cycle, I guess you would reduce the bulk temperature of the contacts, which effectively reduces the ambient temperature seen by the asperities... but it is difficult to do this sort of analysis vs. assuming the worst case of 100% on.

ericjon262

MAR 24, 10:14 PM

I get bored while I wait for parts to get here, and then I do dumb stuff...

Quite possibly the lowest priority thing that I can mess with at the moment... there have been a couple of different goes at the runner placement, then today I decided to leave them off completely, and design the manifold with bolt on runners. I made this decision for a few reasons, if I ever decide to make more than one of these, it will be viable for more than just my car, and it allows me to play with a few other things, plenums, ITB's, ect. The current injector angle is straight down, which should by itself work fairly well, as the intake port is about 45 degrees off vertical, so the injector ends up spraying down the port to the valve. I can take it a step further, and angle the injectors to the front and back of the engine, which would point them directly at the valve. I am curious about the gains that could be had by changing the injector angle, but I don't think it would be very much.